This invention relates to a device for detecting leaks particularly in articles having readily deformable walls.
Generally two basic leak detection methods are known. According to the first method, the article is filled with a test gas and is maintained at a pressure that is higher than that of the surrounding environment. In case of leaks, the test gas escapes from the inside of the article outwardly and is detected there. This method can be characterized as "leak detection from inside to outside" or "leak detection by overpressure". The second leak detection method is, in essence, the reverse of the first method: the pressure difference between the inside of the article and its surroundings is so selected that the pressure within the article is lower than that of the surrounding environment. This can be effected, for example, by vacuumizing the article. According to this method the test gas normally surrounds the article and, in case of a leak, the test gas penetrates into the article and is detected by a test gas detector communicating with the inner space of the article. This method may be characterized as "leak detection from outside to inside" or "leak detection by vacuum."
The above-outlined leak detection methods, however, cannot find application in connection with articles having walls which are readily deformable, because the differential pressure necessary to perform the leak detection would attain or even exceed the stability of the walls, causing significant deformations, damages or even destruction of the walls. The confirmation of fluidtight properties is of primary importance in a number of articles which have such readily deformable walls: thin-walled shipping or storing containers such as barrels for the shipping of products harmful to the environment, fuel reservoirs and the like which, for economic reasons, cannot be manufactured in any other manner.